Barclays Capital has advised clients to batten down the hatches for a worldwide financial storm, warning that the US Federal Reserve has allowed the inflation genie out of the bottle and let its credibility fall “below zero.”

“We’re in a nasty environment,” said Tim Bond, the bank’s chief equity strategist. “There is an inflation shock under way. This is going to be very negative for financial assets. We are going into tortoise mood and are retreating into our shell. Investors will do well if they can preserve their wealth.”

Barclays Capital said in its closely-watched Global Outlook that US headline inflation would hit 5.5pc by August and the Fed will have to raise interest rates six times by the end of next year to prevent a wage-spiral. If it hesitates, the bond markets will take matters into their own hands. “This is the first test for central banks in 30 years and they have fluffed it. They have zero credibility, and the Fed is negative if that’s possible. It has lost all credibility,” said Mr Bond.

The grim verdict on Ben Bernanke’s Fed was underscored by the markets yesterday as the dollar fell against the euro following the bank’s dovish policy statement on Wednesday. Traders said the Fed seemed to be rowing back from rate rises. The effect was to propel oil to $138 a barrel, confirming its role as a sort of “anti-dollar” and as a market reproach to Washington’s easy-money policies.

The Fed’s stimulus is being transmitted to the 45-odd countries linked to the dollar around world. The result is surging commodity prices. Global inflation has jumped from 3.2 to 5pc over the last year. Mr Bond said the emerging world is now on the cusp of a serious crisis. “Inflation is out of control in Asia. Vietnam has already blown up. The policy response is to shoot the messenger, like the developed central banks in the late 1960s and 1970s,” he said.

“They will have to slam on the brakes. There is going to be a deep global recession over the next three years as policy-makers try to get inflation back in the box.”